Today developer Ezio_PS has released a new unofficial build of RetroArch. Check out the release notes and the download link provided below.

Here's another build with new cores and Italian translation.
Changelog ( RetroArch v1.2.2 (Unofficial - Beta v1.6)
Added Mednafen Lynx core, it needs bios in the rom folder
Added Prosystem core, it needs bios in the rom folder
Added Vectrex core, it needs bios in the system or custom folder
Added Stella core, no bios required
Updated Fceumm core, now turbo buttons for player 1 and player 2 work fine
Added the Italian translation
Fixed the code to allow to translate the second to last entry of the help menu
Now the Spanish translation is correctly applied to that entry
Notes:
Mednafen Lynx core has a different compatibility than Handy Lynx,
although both the cores cannot load successfully two roms consecutively
otherwise the homebrew will crash Using Prosystem core some games will
work fine, others will have noticeable glitch or won't work
Vectrex core allow to load fine almost all the roms, but you could get
back to the xmb when you try to close a game